Device for generating and splitting polarized light

Abstract

Disclosed is a polarized light generating device based on an optical waveguide, which includes first to fourth input optical waveguides, respectively, for receiving input light from an outside, first to fifth optical splitters configured to receive at least one light and output the received at least one light as at least one light, and an optical converter configured to receive at least one light from the fifth optical splitter and convert the received light to generate polarized light. The polarized light generating device receives the input light through one of the first to fourth input optical waveguides, and generates a first polarized light, a second polarized light, a third polarized light, and a fourth polarized light. The first to fourth polarized lights belong to elements of two arbitrary two-dimensional mutually unbiased basis sets.

What is claimed is: 
     
         1 . A polarized light generating device based on an optical waveguide comprising:
 first to fourth input optical waveguides, respectively, for receiving input light from an outside;   first to fifth optical splitters configured to receive at least one light and output the received at least one light as at least one light; and   an optical converter configured to receive at least one light from the fifth optical splitter and convert the received light to generate polarized light,   wherein the input light through one of the first to fourth input optical waveguides is received,   wherein, when the input light is received through the first input optical waveguide, a first polarized light is generated, when the input light is received through the second input optical waveguide, a second polarized light is generated, when the input light is received through the third input optical waveguide, a third polarized light is generated, and when the input light is received through the fourth input optical waveguide, a fourth polarized light is generated, and   wherein the first to fourth polarized lights belong to elements of two arbitrary two-dimensional mutually unbiased basis sets.   
     
     
         2 . The polarized light generating device of  claim 1 , wherein the first polarized light is perpendicular to the fourth polarized light, and
 wherein the second polarized light is perpendicular to the third polarized light.   
     
     
         3 . The polarized light generating device of  claim 2 , wherein the first to fourth polarized lights are four different points on a surface of a Poincare sphere representing a polarized light state. 
     
     
         4 . The polarized light generating device of  claim 3 , wherein the first to fourth polarized lights exist on a plane passing through an origin of the Poincare sphere. 
     
     
         5 . The polarized light generating device of  claim 4 , wherein the first to fourth polarized lights are spaced apart from each other at equal intervals on the surface of the Poincare sphere. 
     
     
         6 . The polarized light generating device of  claim 5 , wherein the first optical splitter receives the light from at least one of the second input optical waveguide and the third input optical waveguide,
 the second optical splitter receives the light from at least one of the first input optical waveguide and the first optical splitter,   the third optical splitter receives the light from at least one of the fourth input optical waveguide and the first optical splitter,   the fourth optical splitter receives light from at least one of the second optical splitter and the third optical splitter, and   the fifth optical splitter receives the light from the fourth optical splitter through at least one of two different optical waveguides.   
     
     
         7 . The polarized light generating device of  claim 6 , wherein the polarized light generating device includes:
 a first phase adjuster configured to adjust a phase of the light received from the first optical splitter to output the light to the third optical splitter;   a second phase adjuster configured to adjust a phase of the light received from the fourth optical splitter to output the light to the fifth optical splitter; and   a third phase adjuster configured to adjust a phase of the light received from the fifth optical splitter to output the light to the optical converter.   
     
     
         8 . The polarized light generating device of  claim 7 , wherein the optical converter is composed of a two-dimensional grating coupler, and
 wherein the two-dimensional grating coupler converts a polarization plane of at least one light received from the fifth optical splitter to output the polarized light.   
     
     
         9 . The polarized light generating device of  claim 8 , wherein the two-dimensional grating coupler receives at least one of first light and second light through two different optical waveguides, and
 wherein polarization planes of the first light and the second light are the same.   
     
     
         10 . The polarized light generating device of  claim 7 , wherein the optical converter includes a polarization rotator and a polarization coupler,
 wherein the polarization rotator rotates a polarization direction of the light received from the fifth optical splitter to output the light to the polarization coupler, and   wherein the polarization coupler combines at least one light received from the fifth light splitter and the polarization rotator to output the polarized light through an output optical waveguide.   
     
     
         11 . The polarized light generating device of  claim 10 , wherein the polarization coupler receives at least one of first light and second light through the fifth light splitter and the polarization rotator and
 wherein the polarization planes of the first light, the second light, and the generated polarized light are the same.   
     
     
         12 . The polarized light generating device of  claim 7 , further comprising:
 a controller configured to output a first control signal to control the first phase adjuster, to output a second control signal to control the second phase adjuster, and to output a third control signal to control the third phase adjuster.   
     
     
         13 . A polarized light splitting device based on an optical waveguide comprising:
 an optical converter configured to receive a polarized light from an outside and convert the polarized light to output at least one light;   first to fifth optical splitters configured to receive at least one light and output the received at least one light as at least one light; and   first to fourth output optical waveguides for outputting output light, respectively, and   wherein the at least one output light is output through at least one of the first to fourth output optical waveguides, and   wherein the polarized light is one of elements of two arbitrary two-dimensional mutually unbiased basis sets.   
     
     
         14 . The polarized light splitting device of  claim 13 , wherein the first optical splitter receives at least one light output from the optical converter,
 the second optical splitter receives at least one light from the first optical splitter,   the third optical splitter receives the light from the second optical splitter and outputs the received light to at least one of the first output optical waveguide and the fifth optical splitter,   the fourth optical splitter receives the light from the second optical splitter and outputs the received light to at least one of the fourth output optical waveguide and the fifth optical splitter, and   the fifth optical splitter receives the at least one light from the third optical splitter and the fourth optical splitter, and outputs the received light to at least one of the second output optical waveguide and the third output optical waveguide.   
     
     
         15 . The polarized light splitting device of  claim 14 , wherein the polarized light splitting device includes:
 a first phase adjuster configured to adjust a phase of the light received from the optical converter to output the light to the first optical splitter;   a second phase adjuster configured to adjust a phase of the light received from the first optical splitter to output the light to the second optical splitter; and   a third phase adjuster configured to adjust a phase of the light received from the fourth optical splitter to output the light to the fifth optical splitter.   
     
     
         16 . The polarized light splitting device of  claim 15 , wherein the optical converter is composed of a two-dimensional grating coupler, and
 wherein the two-dimensional grating coupler converts a polarization plane of the polarized light to output at least one light.   
     
     
         17 . The polarized light splitting device of  claim 16 , wherein the two-dimensional grating coupler outputs at least one of first light and second light through two different optical waveguides, and
 wherein polarization planes of the first light and the second light are the same.   
     
     
         18 . The polarized light splitting device of  claim 15 , wherein the optical converter includes a polarization splitter and a polarization rotator,
 wherein the polarization splitter outputs the polarized light received from the outside through an input optical waveguide as at least one light, and   wherein the polarization rotator rotates a polarization direction of the light output from the polarization splitter.   
     
     
         19 . The polarized light splitting device of  claim 18 , wherein the polarization splitter outputs the polarized light received through the input optical waveguide as at least one of first light and second light through two different optical waveguides, and
 wherein polarization planes of the polarized light, the first light, and the second light are the same.